.alpha.-Hydroxyiminophenylacetonitriles are known as intermediates of plant growth promoting agents, agricultural fungicides, or the like (e.g., Japanese Patent Publication No. 62-54096).
As the process of their production, for example, it is also known that .alpha.-hydroxyiminophenylacetonitriles are produced by reacting phenylacetonitriles with alkyl nitrites in an alcohol solvent in the presence of an aqueous base solution, then neutralizing with an acid, removing low-boiling contents by distillation, and collecting the precipitated solids by filtration (e.g., Japanese Patent Laid-open Publication No. 54-163548).
In the case where crude starting materials containing impurities are used as the starting material phenylacetonitriles, however, there is a difficult point that .alpha.-hydroxyiminophenylacetonitriles as the desired products have a decreased purity, if produced by the above process.
In the case where crude materials are used after being purified by distillation or other techniques, there is also a difficult point that complicated steps for separation and purification are required and the yield is decreased by their operations or the like.